Assisted Circulation

Closed-chest circulatory support by pump-oxygenator in experimental ventricular fibrillation at normal temperature.

“…However, Salisbury et al (1959) and Schenk et al (1964) have shown that there is no linear relationship between 'external' work done by the heart and myocardial oxygen consumption and 'internal' work load. Their results indicate that cardiac output must be reduced to zero before myocardial oxygen consumption is consistently reduced.…”

“…Experimentally, Ross, Gilbert, Sharp, and Morrow (1958) in the open-chest animal, and more recently Patterson and Ray (1962) and Johnston, Nield, Pritchard, and Hercus (1965) in the closedchest animal, have pointed to the danger of high left atrial pressures developing during venoarterial bypass in the presence of cardiac arrest or acute left heart failure, due to the accumulating inflow of pulmonary, bronchial, and thebesian blood into the left heart. The left atrial pressure was more likely to rise if it was already high at the start of bypass (a strong possibility in acute left heart failure), and also if the circulatory support flow rate was high (as it may need to be at normal temperature if a reduction in the work load and oxygen consumption of the myocardium is desired (Salisbury, Bor, Lewin, and Rieben, 1959;Schenk, Delin, Camp, McDonald, Pollock, Gage, and Chardack, 1964)). There would be little point in raising the systemic arterial pressure and increasing the coronary flow if pulmonary oedema and acute distension of the left heart resulted.…”